How to integrate Vapi MCP with Codex

Codex is one of the most popular coding harnesses out there. And MCP makes the experience even better. With Vapi MCP integration, you can draft, triage, summarise emails, and much more, all without leaving the terminal or the app, whichever you prefer.

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Api Key

Vapi is a voice AI platform for building, testing, and deploying conversational voice agents. It provides real-time responses and seamless integration for voice-driven applications.

42 Tools

Introduction

Codex is one of the most popular coding harnesses out there. And MCP makes the experience even better. With Vapi MCP integration, you can draft, triage, summarise emails, and much more, all without leaving the terminal or the app, whichever you prefer.

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Why use Composio?

Apart from a managed and hosted MCP server, you will get:

  • CodeAct: A dedicated workbench that allows GPT to write its code to handle complex tool chaining. Reduces to-and-fro with LLMs for frequent tool calling.
  • Large tool responses: Handle them to minimise context rot.
  • Dynamic just-in-time access to 20,000 tools across 1000+ other Apps for cross-app workflows. It loads the tools you need, so GPTs aren't overwhelmed by tools you don't need.

How to install Vapi MCP in Codex

Run the setup command

Run this command in your terminal to add the Composio MCP server to Codex.

Terminal

It will initiate the authentication in a browser window, authorize Codex to access your Composio account.

Composio authentication page

(Optional) Authenticate with OAuth

To authenticate manually, run the login command to open a browser window and authorize Codex to access your Composio account.

bash
codex mcp login composio

Verify the connection

Run codex mcp list to confirm Composio appears as a registered MCP server.

bash
codex mcp list

Codex App

Codex App follows the same approach as VS Code.

  1. Click ⚙️ on the bottom left → MCP Servers → + Add servers → Streamable HTTP:
  2. Fill the header and Key fields with { "x-consumer-api-key" = "ck_*******" }.
  3. The Key is the Composio API key, that you can find on dashboard.composio.dev
  4. Click on Authenticate and authorize Codex to your Composio account and you're all set.
Codex App MCP setup
  1. Restart and verify if it's there in .codex/config.toml
bash
[mcp_servers.composio]
url = "https://connect.composio.dev/mcp"
http_headers = { "x-consumer-api-key" = "ck_*******" }

What is the Vapi MCP server, and what's possible with it?

The Vapi MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Vapi account. It provides structured and secure access so your agent can perform Vapi operations on your behalf.

Conclusion

You've successfully integrated Vapi with Codex using Composio's MCP server. Now you can interact with Vapi directly from your terminal, VS Code, or the Codex App using natural language commands.

Key benefits of this setup:

  • Seamless integration across CLI, VS Code, and standalone app
  • Natural language commands for Vapi operations
  • Managed authentication through Composio
  • Access to 20,000+ tools across 1000+ apps for cross-app workflows
  • CodeAct workbench for complex tool chaining

Next steps:

  • Try asking Codex to perform various Vapi operations
  • Explore cross-app workflows by connecting more toolkits
  • Build automation scripts that leverage Codex's AI capabilities
TOOLS

Supported Tools

Every Vapi action and event your agent gets out of the box.

Update Assistant

Tool to update an existing Vapi assistant configuration.

List Calls

Tool to list calls from Vapi.

Delete Chat

Tool to delete a chat by its ID from Vapi.

Get Chat

Tool to fetch chat details by ID.

Create Analytics Queries

Tool to create and execute analytics queries on VAPI data.

Create Assistant

Tool to create a new Vapi assistant with specified transcriber, voice, and AI model configurations.

Create Eval

Tool to create an eval for testing conversation flows.

Create OpenAI Chat

Tool to create an OpenAI-compatible chat using the Vapi API.

Create Phone Number

Tool to create a phone number with Vapi.

Create Monitoring Policy

Tool to create a monitoring policy in VAPI.

Create Provider Resource

Tool to create an 11Labs pronunciation dictionary resource.

Create Scorecard

Tool to create a scorecard for observability and evaluation.

Delete Call

Tool to delete a call by its unique identifier.

Delete Eval

Tool to delete an eval by ID.

Delete Phone Number

Tool to delete a phone number from Vapi.

Get Eval

Tool to retrieve an eval by its ID.

Delete Eval Run

Tool to delete an eval run by its ID from Vapi.

Update Eval

Tool to update an existing eval in Vapi.

Get Assistant

Tool to retrieve a specific assistant by ID from Vapi.

Get Call

Tool to fetch call details by ID.

Get File

Tool to retrieve a file by its ID from Vapi.

Get Insights

Tool to retrieve insights from Vapi.

List Monitoring Policies

Tool to retrieve monitoring policies from Vapi.

Get Observability Scorecard

Tool to list observability scorecards with optional filtering and pagination.

List Provider Resources

Tool to list provider resources from Vapi.

List Structured Outputs

Tool to list structured outputs with optional filtering.

Get Insights

Tool to retrieve insights from VAPI.

List Assistants

Tool to list all assistants in your VAPI organization.

List Chats

Tool to retrieve a list of chat conversations from VAPI.

List Evals

Tool to retrieve a paginated list of evals from Vapi.

List Provider Resources

Tool to retrieve provider resources from Vapi (e.

Update Insight

Tool to update an existing insight configuration in VAPI.

Create Phone Number

Tool to create a phone number with VAPI.

List Scorecards

Tool to retrieve a paginated list of scorecards from Vapi.

Create Session

Tool to create a new session in Vapi.

List Sessions

Tool to retrieve a paginated list of sessions from VAPI.

List Structured Outputs

Tool to list structured outputs with optional filtering and pagination.

Get Tool

Tool to fetch tool details by ID.

Test Code Tool Execution

Tool to test TypeScript code execution in Vapi's code tool environment.

Update Tool

Tool to update an existing Vapi tool configuration.

Update Phone Number

Tool to update an existing phone number configuration in VAPI.

Upload File

Tool to upload a file to Vapi Knowledge Base.

FAQ

Frequently asked questions

With a standalone Vapi MCP server, the agents and LLMs can only access a fixed set of Vapi tools tied to that server. However, with the Composio Tool Router, agents can dynamically load tools from Vapi and many other apps based on the task at hand, all through a single MCP endpoint.

Yes, you can. Codex fully supports MCP integration. You get structured tool calling, message history handling, and model orchestration while Tool Router takes care of discovering and serving the right Vapi tools.

Yes, absolutely. You can configure which Vapi scopes and actions are allowed when connecting your account to Composio. You can also bring your own OAuth credentials or API configuration so you keep full control over what the agent can do.

All sensitive data such as tokens, keys, and configuration is fully encrypted at rest and in transit. Composio is SOC 2 Type 2 compliant and follows strict security practices so your Vapi data and credentials are handled as safely as possible.

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